Stop motion device for knitting machines



p 1941. A. CRAWFORD 2,257,037

STOP MOTION DEVICE FOR KNITTING MACHINES Filed April 5, 1939 PatentedSept. 23, 1941 STOP MOTION DEVICE FOR KNITTING MACHINES Alfred Crawford,New Brunswick, N. J., assignor to Crawford Manufacturing Company, NewBrunswick, N. J a corporation of New Jersey Application April 3, 1939,Serial No. 265,822

12 Claims.

This invention relates to faulty-needle and snarled-thread detectors,for use with electrically-operated stop motions of knitting machines,such, for example, as the stop motions disclosed in my prior U. S.Patents No. 1,992,860, dated February 26, 1935 and No. 2,145,754 datedJanuary 31, 1939, which latter constitutes an improvement over thestructure disclosed in the earlier patent,

In each of the above noted cases, broken or bent needles or latches, orthread snarled or bunched on a needle as a result of the improperoperation of the needle or its latch, or which results from a knot orother irregularity in the knitting thread or in the knitting operation,are detected by purely mechanical means. The mechanical devices includea detector finger which is arranged to engage or to be engaged by afaulty needle or a snarled bunch of thread. The finger, in turn,controls a spring-loaded plunger arranged, when released, to drop behindone of a series of abutments formed on a floating ring which is looselymounted for rotation in a circular groove formed in the frame of theknitting machine, concentric to the axis of the needle cylinder. leversand links designed to interrupt the application of power to the machineand to apply a brake for overcoming the momentum of the machine, as aresult of operation ofthe primary detecting finger.

When using constructions such as noted above, there is a certain amountof delay in the stopping of the machine after the detecting finger hasbeen initially actuated, due to there being a certain amount of rotationof the machine parts required to release the plunger, for the plunger toengage an abutment on the ring, and for the ring to trip the powerinterrupting and brakeapplying mechanism.

The primary object of the present invention is to provide an electricaldetector which may be connected in the same electrical circuit as thedetectors disclosed in said patents for slack, taut or broken threads,whereby actuation of the needle or snarled-thread detcetor willimmediately actuate the trip motor of the stop motion, in the samemanner as the other thread detectors of the stop motion, wherebyinterruption of the power to the machine and the application of thebrake Will be effected immediately upon operation of the needle andsnarled-thread detector.

The mechanical detector above noted also requires that an annular spacebe reserved com- The ring, in turn, operates a train of pletely aroundthe needle cylinder andits cam ring, outside the latter, for the plungermechanism and the ring to operate in. The necessity for providing suchspace has prevented the placing of attachments on the frame of themachine in close proximity to the needle cylinder or its cam ring.

Another object of the invention, therefore, is to construct a needle andsnarled-thread detector in a manner making it possible to eliminate theplunger, ring, and other mechanical connections formerly required tostop the machine by operation of the needle and snarled-thread detectorand which necessitated the reservation of lost space, outside thecylinder and cam ring.

Another object is to .construct'the device in such a manner that it maybe mounted above the upper end of the needle cylinder, to'operate withina circle of a diameter substantially no greater than the outsidediameter of the needle cylinder and less than that of the cylinder camring, whereby the space normally required for operation of themechanical detector and the ring forming part thereof may be utilizedfor the placing of other attachments close to the cylinder and cam ring.

Another object of the invention is to construct the device in such amanner that upon operation of the sensitive element by engagementthereof with a knot, etc., said element will be automatically moved outof engagement with the obstruction upon effecting operation of the stopmotion.

The construction and operation of detector devices made and mounted onknitting machines in accordance with the principles of the presentinvention will be fully disclosed hereinafter, reference being had tothe accompanying drawing of which Fig. 1 is a perspective view ofthepreferred form of a detector device constructed and adapted tooperate in accordance with the present invention;

Figs. 2 and 3 are side elevations of the detector device mounted on thedial cam plate of a rib knitting machine, or ona corresponding cap platefrequently arranged atthe otherwise open end of the needle cylinder of aplain non-rib knitting machine with the device in its normally setcondition in Fig. 2 and tripped in Fig. 3;

Fig. 4 is a rear elevation of the device;

Fig. 5 is a sectional elevation taken on the line 5-5, Fig. 4, showingthe detector in a set position, as in Fig. 2;'

rotatably mounted a detector shaft 20.

I is provided with the usual vertical grooves 2 in which the cylinderneedles 3 are vertically re-' ciprocated, in the usual manner.

In some instances plain knitting machines are provided with a horizontalplate It]; axially aligned with the needle cylinder l and positionedadjacent the normally open'upper end of the needle cylinder, such platebeing supported in" the manner disclosed in the above mentioned patents.The plate I normally supports the thread feeding mechanism and othercomponents orthe machine.

in the present instance the plate in repre-.

sents the dial cam plate ofa rib knitting machine and is disposed insuperposed relation to the needle dial 'plate 9 which is provided withthe usual radial grooves 8 in which the dial needles 1 are "slidablymounted for radial reciprocation by earns carriedbythe camplate H). V

The detector device of the present invention comprises a substantiallyrectangular bod-y eleinent H which may take the form of a solid casting'or a suitable hollow casing which in either case includes a 'backwall12, side walls l3 and M re pectively, top and bottom walls l5 and I5respectively, and a front wall 11.

Pi'vot'ed to the body eleinentll adjacent each of the side walls l3 andI4 is a lever I8 which is provided with an integrally formed outwardlyprojecting boss 19. 'In the boss or bearing I9 is Near the outer end ofthe detector shaft 20, said, shaft is drilled transversely for receptionof the upper end of an adjustably mounted detecting finger 2!. Thefinger ;2l,;as shown-in Figs. 1 and 2 is provided with a pointed lowerend 22. The pointed 7 end 22 of the'detector finger 2! normally liesimmediately adjacent and substantially parallel -to the outer faces ofthe cylinder needles 3, and terminates at a point immediately adjacentand above the upper faces of the dial needles I, to be engaged by eitherthe cylinder or dialneedles if bent from their normal positions or bythe latches 5 and 6-of the cylinder needles 3 anddial needles 1-.respectively, under irregular conditions, or. by the knitting threada: should such thread bunch up on one or the other of the needles andproject into the angle formed between the outer andupper surfaces o'fthecylinder and, dial needles respectively.

T e needle detector 2| is offset longitudinally below the shaft 20, asindicated at 23, whereby,

upon loosening the set screw 24 which is mounted in the outer end of theshaft 2;), the pointed end 22 0f the detector finger 2 I may be swungabout r the axis o'f-the' upper main portion of the finger 2i andthereby moved toward or away from the 1 cylindern'eedles 3, by rotationofthe finger 2i i lntheshaftQQ; and moved toward or away from the dialneedles 1 by axially sliding the finger 2| in its transversely extendingbearing in the shaft 23, i. eat right angles to the axisof the shaft.after whichtightening of the set screw 24 will retain the linger in itsdesired position.

The body element l l is provided with a foot or bracket which may beformed as a part of the casing or separately therefrom and securedthereto by any suitable means, such, for example, as by screws 26. Thefoot 25 has a slot 21 for passage of screws 28 by which the device issecured to the plate l0.

Axial movement of the shaft 23 relative to the boss I9 is prevented, inone direction, by a collar 29 secured to the shaft and bearing againstthe outer end of the boss 19 and. in the opposite direction, by a lever30 which is secured to the inner end of the shaft 20, between the innerend of the boss lil and the frontface ll of the body element H, as by adowel, set screw or riveting, by which it is retained against relativerotation and axial .movementwith respect to the shaft 2i].

The upper end of the lever 38, when the detector finger 2 1 is set, isadapted to rest in a recess 32' which is formed in a cam or guide plate33. The guide plate 33 is secured to the top surface !5 of the bodyelement II by screws 34, 34 as shown in- Fig. '7. The recess 32 isformed by the intersection of two right angle shoulders 35 and 36.The'cam or guide plate 33 also includes a cam or guide surface 31 whichextends at an angle to the surface of the shoulder 36 and inter-' sectssaid surface in spaced relation to the intersection of the surface ofthe shoulder 33 with the surface of the shoulder 35. v

The lever I3 is of forked construction having arms 38 and 39 disposed atopposite sides of the body element H adjacent the opposite side walls orfaces 13 and I4 respectively. A pivot shaft 40 extends through thearms'38 and 39 and the body element ll therebetween and provides apivotal connection between the lever l8 and the body element H.

The pivot shaft 40 is diametrically reduced a that end which fits intothe arm 39 as indicated at 4! and is provided with a shoulder 42 whichis held firmly against the inner surface of the arm 39 by a clamp screw43, the underside of the head of which bears against the outer surfaceof the arm 39 and clamps the shaft or rod 4!] to the lever l8 forconcurrent rocking motion therewith. A set screw 44 tapped into the arm39 bears against the reduced portion 4! of the shaft 40 and aids inretaining the shaft :43 in fixed relation to the lever 18 after circularadjustment between the two hasbeen effected.

The arm 38 is provided with an enlarged opening 45 through which theshaft 43 projects. A torsion spring 46 encircles the shaft 40 within therecess 45 and has one end 41 anchored in a head 48 formed on the shaft40 and its opposite end 49 anchored in an opening 53 formed in the bodyelement I l. The spring 46 tends to rock the lever l8 and shaft 40 fromthe set position shown in Fig. 2 to the tripped position shown in Figs.3 and l and the force of the'spring as exerted against the lever I8 maybe minutely controlled by adjusting the shaft 43 in the lever l8 byrotating the one with respect to the other and thereafter tightening theholding screws 43 and 44.

The spring 43 normally maintains the end 3! of the lever 30 in contactwith the shoulder 33 of the recess 32 in the guide plate 33 and saidshoulder 36 normally prevents rocking of the lever l8 from the "setposition to the tripped" position. V

The upper end 3| of the lever '30 is normally retained in contact withthe shoulder 35 while the lever I8 is in the set position by a torsionspring 5| which encircles the shaft 20 within a recess 52 formed in theouter end'of the boss or bearing |9. One end 53 of the spring 5| isanchored in an opening 54 formed in the base of the recess 52 while theopposite end 55 of the spring 5| is anchored in a corresponding openingformed in the collar 29. The force exerted by the spring 5| in adirection to keep the upper end 3| of the lever 30 in contact with theshoulder 35 of the plate 33 may be minutely regulated by turning thecollar 29 with respect to the shaft 20 and thereafter securing thecollar rigidly to the shaft by tightening the set screw 56 which isthreaded into the collar 29.

From the above it will be clear that when the finger 2| is in the setposition shown in Fig. 2 the upper end 3| of the lever 30 is held firmlyin contact with the shoulders 35 and 36 of the recess 32 formed in theplate 33 by the combined efforts of the springs 46 and 5|. It will alsobe apparent that relative rotation between the plate l and the cylinderI or the dial 3 will cause the finger 2| to travel around the needles 3and I or vice versa and should any obstruction be presented to the lowerend 22 of the detector finger 2| during such relative rotation thefinger 2| will swing about the axis of the shaft 20 in the direction ofthe arrow 3 Fig. 1 thereby rotating the shaft 20 and the lever 3|) andcausing the upper end 3| of said lever to slide along the shoulder 36out of contact with the shoulder 35 until the point of intersectionbetween the surface of the shoulder 36 and the edge 31 of the cam plate33 is reached, such action taking place in opposition to the spring 5!When the upper end 3| of the lever 30 moves ofi the shoulder 36 thespring 46 then becomes effective to swing the lever |8 upwardly in thedirection of the arrow 2, Fig. 1. Such movement of the lever It causesthe upper end 3| of the lever 30 to slide along the inclined surface 31of the fixed guide plate 33 thereby causing a further rotary movement ofthe shaft 28 in the direction of the arrow y, Fig. l.

The above noted universal movement of the detector finger 2| causes thelower end 22 of said finger to be immediately removed from contact withthe obstruction by which the tripping of the device has been effected.

The pivot shaft 4|] is provided with a laterally extending pin or otherprotuberance 51 which lies in a vertical slot 58 formed in the rear facei2 of the body element II. This protuberance 51, in the presentinstance, constitutes one element of an electrical circuit breaker orswitch, the second element of which, in the present instance, is in theform of a thin flexible blade 60.

The blade 63 constitutes a relatively fixed contact element of theswitch and is rigidly secured at its upper end to a binding post 6|which is mounted in an insulating sleeve 62. The lower end of the blade69 projects below the sleeve 62 to provide for flexing of the blade. Theinsulating sleeve 62 is secured by a nut 63 in an opening formed in theupper end of the body element One end of an electrical conductor 65 ispermanently secured to the outer end of the binding post 6| in anysuitable manner, as by a screw 66. The conductor 65 is electricallyinsulated from any and all other parts of the element H and themechanism carried by the element The conductor 65 may be connected toone side of the coils of the stop motion trip motor M, as shown in Fig.8. The opposite side of the motor coils may be connected to one side ofa suitable current supply circuit. The second side of the current supplycircuit may be connected to the machine proper, which forms one side ofthe stop motion circuit and includes the plate I ll, the foot 25, andbody element The shaft 20 and the collar 29 thereon, being in electricalcontact with the lever l8, and the lever l8 being in electrical contactwith the rock shaft 40, carries the current of the second side of thestop motion circuit to the protuberance 51. The protuberance5'l'functions as the movable contact element of a switch, of which therelatively fixed contact element is formed by the blade 60.

Rocking of the shaft 4|! in opposite directions brings the switchelement 58 into and out of electrical contact with the switch element 60and completes or interrupts the circuit through the trip motor M.

When the detecting finger 2| is engaged by a faulty needle or snarledthread, said detector finger is swung thereby from the set positionshown in Figs. 2 and 5 to the tripped position shown in Figs. 1 and 3,wherein the protuberance 58 engages and makes electrical contact withthe switch blade 60, thus completing the trip motor circuit, by whichstopping of the machine is effected immediately.

The device may be reset by merely pressing the outer end of the lever Bdownwardly against the action of the spring 46, which causes the upperend 3| of the lever 30 to ride outwardly along the cam edge 31 of theguide plate 33 until the lever end 3| snaps across the shoulder 36 intocontact with the shoulder 35, by action of the spring 5|.

.From the above it will be clear'that the device is of simple ruggedconstruction and is very effective in, quickly stopping the machine towhich it is attached, without necessity of the finger 2| moving to anymaterial extent relative to the needles after the lower end 22 of thedetector finger 2| engages any sort of an obstruction in its path. Byswinging upwardly when tripped the detector finger 2| is carried awayfrom the obstruction, leaving the same clear for removal by the operatorwhen the machine stops.

I claim:

1. In an obstruction detector for knitting machines, the combination ofa detector finger having one end adapted to be normally positionedadjacent the needles of a knitting machine for movement laterally withrespect thereto in a path adjacent said needles during normal operationof the machine, means supporting said finger for pivotal movement in avertical plane substantially coincident with said path, and meanssupporting said finger for pivotal movement in a vertical planetransverse to said path.

2. In an obstruction detector for knitting machines, the combination ofa detector finger having one end adapted to be normally positionedadjacent the needles of a knitting machine for movement laterally withrespect thereto in a path adjacent said needles during normal operationof the machine, means supporting said finger for pivotal movement in avertical plane substantially coincident with said path, means supportingsaid finger for pivotal movement in a vertical plane transverse to saidpath, and an electric circuit controlling device operable by the pivotalmovement of said finger in one of said planes.

3. In an obstruction detector for knitting machines, the combination ofa detector finger having one end adapted to be normally positionedadjacent the needles of a knitting machine for movement laterally withrespect thereto in a path adjacent said needles during normal oper ationof the machine, means supporting said finger for'pivotal movement in avertical plane substantially coincident with said -path,;-meanssupportingsaid finger for pivotal movement in a vertical planetransverseto said path and'an electric circuit controlling deviceoperable by one and controlled by the other of said pivotal movements ofsaid fingen 4. In anobstruction detector for knitting machines, thecombination of a detector finger have ing one end adapted to be normallypositioned adjacent the needles of a knitting machine for movementlaterally :with respect thereto in a path adjacent said needles duringnormal-operation of .themachine, means supporting said finger forpivotal movement in a plane substantially coincident with said path,means supporting said finger for pivotal movement in a plane transverseto said path, an electric circuit controlling device operable by one andcontrolled by the other .of said pivotal movements of said finger andcomprising a contact carried by one of said supporting means and acontact operatively connected to said finger for movement relative tothe first said contact by rocking movement of said finger.

5. In an obstruction detector for knitting machines, the combination ofa detector finger having one end adapted to be normally positioned ationof, the machine, a rock shaft supporting said finger for rockingmovement in avertical plane substantially coincident with said path, alever supporting said rock shaft for rocking movement of said finger ina vertical plane transverse to said path, a body element mountedadjacent said path, and a rock shaft pivotally mounted in said .bodyelement with said lever mounted on said last rockshaft.

a 9. In an obstruction detector for knitting machines, the combinationof a detector fingerhaving one end adapted to be normally positionedadjacent the needles of a knitting machine for adjacent theeneedles of aknitting machine for V movement laterally with respect thereto 'in apath adjacent said needles during normal oper ation of the machine,means comprising a rock shaft and mounting for supporting said fingerfor pivotal movement in a vertical plane substantially coincidentwithsaid path, and means comprising a second rock shaft and mounting forsupporting said finger for pivotal movementin a vertical planetransverse to said path; I

6. In an obstruction detector for knitting machines, the combination ofa detector finger having one endeadapted to be normally positionedadjacent the needles of .a knitting machine for movement laterally withrespect thereto in a path adjacent said needles during normal operationof the machine, means comprising a rock shaft and mounting forsupporting said finger for pivotal movement in a plane substantiallyco-, incident with said path, means comprising a second rock shaft andmounting for supporting said finger for pivotal movement in a planetrans- Verse to said path, an electric circuit controlling devicecomprising a contact carried by one of said mountings, and a contactcarried by the rock V shaft associated with the last said mounting andoperable by the rocking of the shaft relative to the mounting.

-'Z.- In an obstruction detector for knitting machines, the combinationof a detector finger having one end adapted. to be normally positionedadjacent the needles of a knitting machine for movement laterallywithrespect thereto in a path adjacent said needles during normaloperation of the machine, a rock shaft supporting said finger forrocking movement'in a vertical plane substantially coincident with saidpath, a lever supporting said rock shaft for rocking movement of saidfinger in a vertical plane transverse to said path, and means pivotallysupporting said lever adjacent said path.

8. In an obstruction detector for knitting machines, the combination ofa detector finger having one end adapted to be normally positionedadjacent the needles of a knitting machine for emovement laterally withrespect thereto in a path adjacent said needles during normal oper-"movement laterally with respect thereto in a path adjacent said needlesduring normal operation of the, machine, a rock shaft supporting saidfinger for rocking movement in a plane substantially coincident withsaid path; a lever supporting said rock shaft for rocking movement ofsaid finger in a plane transverse to said path, a body element mountedadjacent said path, a rock shaft pivotally mounted in said body elementwith said lever mounted on and locked to said last rock shaft, a fixedcontact carried by said body element, and a movable contact carried by,the'rock shaft mounted in said body element and operable With respectto said fixed contact by rocking'of said lever. V

10, In an obstruction detector for a knitting machine provided with aseries of needles havinghook-ends arranged in a circle, the combinationof adetector finger adapted to have one end normally disposed adjacentsaid needles for concentric relative rotation between the finger and theneedles about the axis of said circle, means for supporting said fingerforsaid relative rotation including a body element, a rock shaft carriedby said body element with the axis of the rock shaft disposed at rightangles to a plane coincident with and extending radially from the' axisof said:circ1e, a lever secured to said rock shaft,. a second rock shaftcarried by said lever with its-axis at right angles to the axis of thefirst said rock shaft, said finger being secured to said second rockshaft in spaced relation to the axis of said first rock shaft, aretaining plate carried by said body element, a retaining lever on saidfinger supporting rock shaft normally engaging a shoulder on saidretaining plate, and resilient means normally maintaining said retaininglever in contact with said shoulder for maintainingsaid finger in saidnormal position.

11. In an obstruction detector for a knitting machine provided with aseries of needles having hook ends arranged in a circle, the combinationof a detector finger adapted to have one end normally disposed adjacentsaid needles for con- 7 centric relative rotation between the finger andthe needles about the axis of said circle, means for supporting saidfinger for said relative rotation including a body element, a rock shaftcarried by said body element with the axis ofthe 7 ders on saidepl'ate,resilient means retaining said lever in contact with said shoulders, anda cam surface on said plateadjacent one of said shoulders for engagementby said retaining lever upon release from said shoulders foradditionally rocking said finger supporting shaft after initial rockingthereof by an obstruction which effects release of said retaining leverfrom said shoulders.

12. In an obstruction detector for a knitting machine provided with aseries of needles having hook ends arranged in a circle, the combinationwith its axis at right angles to the axis of the first said rock shaft,said finger being secured to said second rock shaft in spaced relationto the axis of said first rock shaft, a retaining plate carried by saidbody element, a retaining lever on said finger supporting rock shaft, apair of shoulders on said plate, resilient means retaining said lever incontact with said shoulders, a cam surface on said plate adjacent one ofsaid shoulders for engagement by said retaining lever upon release fromsaid shoulders for additionally rocking said finger supporting shaftafter initial rocking thereof by an obstruction which effects release ofsaid retaining lever from said shoulders, a fixed contact carried bysaid body element, and a movable contact carried by said leversupporting rock shaft for engagement with the fixed contact as a resultof initial rocking of said finger.

' ALFRED CRAWFORD.

